foundationdb/contrib/ddsketch_compare.py
Kevin Hoxha 058276493f
ddsketch_utility: Add utility scripts for ddsketch (#7602)
* Adds ddsketch_calc.py which implements a class for DDSketch related calculations
* Adds ddsketch_conversion.py for quickly computing a bucket index to a value or vice-versa
* Adds ddsketch_compare.py to compute how similar two ddsketch distributions are
* Adds export_graph.py to graph the ddsketch distribution outputted from mako

The arguments for ddsketch_conversion.py are:
-b, --bucket: the bucket index that we need to calculate the value from (optional)
-v, --value: the value that we need to calculate the bucket index from (optional)
-e, --error_guarantee: the error guarantee for ddsketch (optional, default is 0.005)

The arguments for ddsketch_compare.py are:
--file1: Path to first ddsketch json
--file2: Path to second ddsketch json
--txn1: The transaction type for the first file
--txn2: The transaction type for the second file
--op: The operation name (ex: GRV, GET ...)

The arguments for export_graph.py:
--file: path to ddsketch distribution
--txn, -t: Transaction type from file
--title: title for graph (optional, otherwise "Title" is used)
--savefig: Path to save the image plot (optional)
--op: Which operation to plot
2022-07-25 10:29:33 -07:00

70 lines
2.5 KiB
Python

#!/usr/bin/env python3
#
# ddsketch_compare.py
#
# This source file is part of the FoundationDB open source project
#
# Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import argparse
import json
import numpy as np
# kullback-leibler divergence (or relative entropy)
def relative_entropy(p, q):
difference = 0.0
for i in range(len(p)):
if p[i] != 0.0 and q[i] != 0.0:
difference += (p[i] * np.log2(p[i]/q[i]))
return difference
# jensen-shannon divergence (or symmetric relative entropy)
def relative_entropy_symmetric(dd1, dd2):
# normalize p, q into distribution
sum1 = sum(dd1)
sum2 = sum(dd2)
p = [dd1[i] / sum1 for i in range(len(dd1))]
q = [dd2[i] / sum2 for i in range(len(dd2))]
m = [0.5 * (p[i] + q[i]) for i in range(len(p))]
return 0.5 * relative_entropy(p, m) + 0.5 * relative_entropy(q, m)
# setup cmdline args
parser = argparse.ArgumentParser(description="Compares two DDSketch distributions")
parser.add_argument('--txn1', help='Transaction type for first file', required=True, type=str)
parser.add_argument('--txn2', help='Transaction type for second file', required=True, type=str)
parser.add_argument('--file1', help='Path to first ddsketch json', required=True, type=str)
parser.add_argument('--file2', help="Path to second ddsketch json'", required=True, type=str)
parser.add_argument("--op", help='Operation name', type=str)
args = parser.parse_args()
f1 = open(args.file1)
f2 = open(args.file2)
data1 = json.load(f1)
data2 = json.load(f2)
if data1[args.txn1][args.op]["errorGuarantee"] != data2[args.txn2][args.op]["errorGuarantee"]:
print("ERROR: The sketches have different error guarantees and cannot be compared!")
exit()
b1 = data1[args.txn1][args.op]["buckets"]
b2 = data2[args.txn2][args.op]["buckets"]
re = relative_entropy_symmetric(b1, b2)
print("The similarity is: ", round(re, 8))
print("1 means least alike, 0 means most alike")